ABSTRACT
Deterioration of wall paintings caused by biological agents is a serious problem throughout the world. They can deteriorate under the influence of biotic and abiotic factors in the environment unless special measures are taken to conserve them. For example, in the Lascaux cave in France the green infection of wall paintings has been reported to be due to bacteria carried on the shoes and sweat of visitors (Lefevre, 1974); consequently the caves have been closed to visitors. The microorganisms develop on the paintings only if the relative humidity of the surroundings exceeds 75% and temperature ranges between 5 and 40°C The early stages of attack by biological agents are relatively easy to control, but once such an attack is widespread it is extremely difficult to deal with.
